Throttle body assemblies provide aspiration to engines. The aspiration to these engines is controlled through a throttle plate disposed in a bore of the throttle body assembly. The throttle plate is manipulated by a user of the engine to cause increase or decrease the flow of air to the engine thereby controlling power output.
As part of an overall engine control system, and in certain applications a vehicle control system, the operation of the throttle body assembly is monitored to provide vital information to the control system. For example, as part of an overall monitoring system of an engine, it is desirous to monitor the position of a throttle plate to ensure that the throttle body assembly is functional and performing properly. Also, by determining the position of the throttle plate it is possible to determine efficiency of the engine by comparing anticipated power output to actual power output.
In the past, position of the throttle plate has been determined using throttle position sensors. These sensors utilized induction formed between a component of the throttle plate and the throttle position sensor. More particularly, a detectable element is often mounted to a shaft in which the throttle plate has been mounted to and is placed in inductive relationship with a sensor element such that position of one or more components of the detectable element relates to a position of the throttle plate.
While these systems work generally well, there are still improvements necessary to improve performance and reduce cost of the throttle position sensor. In one aspect, the formation and attachment of a detectable element to the shaft of the throttle plate can be time consuming and costly. For example, it is necessary that the detectable element is particularly angularly aligned with respect to the throttle plate to ensure that readings from the sensor element correspond to actual positions of the throttle plate. It is also necessary that the detectable element is particularly aligned, with respect to a shaft of the throttle plate, to ensure that the surface of the detectable element is parallel with respect to the sensor element. Furthermore, it is highly important to ensure that detectable element maintains it position, both radially and axially, with respect to sensor element to prevent inaccurate readings or total failure of the throttle position sensor.
Prior methods to securely attach detectable elements to a throttle plate have involved the use of laser welding. However, the use of laser welding is difficult, time consuming and costly. Further, heat generated through laser welding could potentially warp the material of the detectable element, throttle plate shaft or both.
In view of the foregoing, there is a need for improved methods and devices for monitoring position of a throttle plate. More so, there is a need for improved methods and devices for the formation and attachment of throttle position sensor components to a throttle body assembly.